[X86] Fix cpu name typos

As discussed on PR26418 rGea84dc9500df incorrectly set the knl cpuname to tremont (and missed out the tremont cpuname entirely).

(cherry picked from commit 0d17dc2)

Author: RKSimon

llvm/lib/Support/Host.cpp

@@ -760,14 +760,15 @@ getIntelProcessorTypeAndSubtype(unsigned Family, unsigned Model,
       *Type = X86::INTEL_GOLDMONT_PLUS;
       break;
     case 0x86:
+      CPU = "tremont";
       *Type = X86::INTEL_TREMONT;
       break;
 
+    // Xeon Phi (Knights Landing + Knights Mill):
     case 0x57:
-      CPU = "tremont";
+      CPU = "knl";
       *Type = X86::INTEL_KNL;
       break;
-
     case 0x85:
       CPU = "knm";
       *Type = X86::INTEL_KNM;